This invention relates to wheels for skates such as inline skates, and, in particular, to skate wheels constructed to minimize wheel weight.
The popularity of roller skating and more particularly inline skating has increased dramatically in recent years. Inline skating speed competitions or races have simultaneously emerged as a popular sporting event. One existing problem with current inline skates used in racing pertains to the relatively heavy weight of the skate which physically burdens the racer and hinders his/her timed performance.
Current inline skates are essentially composed of three components, namely the shoe, the skate wheels, and the frame which mounts the wheels to the boot. In an effort to minimize skate weight and improve racing times, the shoe in some racing inline skate models has been modified to be constructed from lighter plastics or composite materials. Moreover, the heavy steel frames previously used to mount the wheels have been replaced with lightweight but sufficiently strong materials such as aluminum. Despite these improvements, and in order to optimize performance times as well as gain an advantage over fellow competitors utilizing heavier skates, it is still desirable to further lower skate weight by providing lighter weight skate wheels.
Existing inline skate wheel technology is deficient from a weight standpoint for racing competitors for a number of reasons. Typical inline skate wheels employ an injection molded plastic hub having an elastomeric ground engaging tread disposed circumferentially around the plastic hub. Because manufacturers have heretofore attempted to provide skate wheels with a significant operational life, a considerable thickness of elastomeric tread is utilized. For a thicker tread of a given composition, a longer period of wheel use is generally required before the elastomeric tread is worn away to expose the plastic hub. While for many consumers longer wheel life is desirable from a cost standpoint as frequent expensive wheel replacement is not necessitated, the excess tread on the skate wheel not worn off during use must be carried by a skater during the entire competition. A small amount of excess tread on each wheel, multiplied by the number of wheels on such skates, results in a weight burden which wastes valuable racer energy. In addition, the large amount of elastomeric tread causes the wheel to be less rigid overall and as a result is likely to deform and absorb energy rather than transmit energy and increase a skater's speed.
Despite having an advantageous lesser density than metal hubs of the past, the injection molded plastic hub common in inline skate wheels today is also less than ideal for racing. Because the plastic material used to form the hubs is of a limited strength or rigidity, a tradeoff exists between hub rigidity and hub weight. In particular, to make the skate wheel as light as possible, the hubs can be fabricated from a minimal amount of plastic material. However, because these plastic hubs will have a lesser rigidity than hubs constructed from a greater amount of plastic, they tend to experience more multi-directional deformation under strain, which translates to greater wheel wobble when a skater applies a force, for example during turning or pushoff, to the wheel. This deformation dissipates valuable energy. On the other hand, more substantial plastic hubs are less prone to experience wheel wobble. Yet, the more rigid hub translates to a detrimental greater wheel weight which burdens the skater throughout a competition. Thus, it is desirable to provide an inline skate wheel which, while being rigid and strong enough to withstand forces experienced during operation, is constructed to have a limited weight for optimizing timed racing performances.
Another problem with many inline skate wheels is encountered when the tread wears out. Because the user typically can not replace the tread on the skate wheel, the entire skate wheel is discarded despite the fact that the wheel hub itself is still capable of further operation. Thus, it is desirable to provide a skate wheel which provides a replaceable tread to allow a user to further utilize a wheel hub after the present tread expires.